[Issue 6777] alias this disables casting for classes

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=6777

--- Comment #8 from Sobirari Muhomori <dfj1esp02 at sneakemail.com> ---
Workaround:
---
class A { int a; alias a this; }
class B:A { int b; }

int main()
{
    A a = new B;
    //B b = cast(B)a;
    Object obj = a;
    B b = cast(B)obj;
    assert(b.b==0);
    return 0;
}
---

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